Not much poeple go to subdomains, so I sugest maybe get a free domain or a real one for example: www.downloadheaven.com or www.downloadheaven.org
But if you are not wanting to pay, maybe get a free domain for example: www.downloadheaven.co.cc or www.downloadheaven.co.nr or www.downloadheaven.tk
To get a free domain go to either: http://www.co.cc - http://www.co.nr - http://www.tk ...ect
But if you want to get a real domain (costs monthly, yearpay or full). Just serahc in google "cheap domain" or something simuliar to that.
Also your site needs to look good and have a good reason to be up and running.
For example, a gaming website needs lots and lots of games, hacks, cheats, downloads, news and maybe events...
A downloads site, needs lots of downloads from many catagories...
Also your site needs a good design and maybe a logo.
I hope I have helped. Best Regards,